I upgraded Ubuntu from 20.04LTS to 22.04LTS and now my Ubuntu Software GUI is not working anymore it is not opening at all. I have googled the entire internet and nothing works. I removed and installed gnome-software. When I tried sudo apt install --reinstall software-center it gave me the error: package software center has no installation candidate. What does that even mean? What can I do to use my Software Center again?

EDIT:

The command cat /etc/apt/sources.list outputs the following:

jan@Ubuntu-20-04:~$ cat /etc/apt/sources.list

# deb cdrom:[Ubuntu 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1)]/ focal main restricted



# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to

# newer versions of the distribution.

deb http://nl.archive.ubuntu.com/ubuntu/ jammy main restricted

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal main restricted



## Major bug fix updates produced after the final release of the

## distribution.

deb http://nl.archive.ubuntu.com/ubuntu/ jammy-updates main restricted

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal-updates main restricted



## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu

## team. Also, please note that software in universe WILL NOT receive any

## review or updates from the Ubuntu security team.

deb http://nl.archive.ubuntu.com/ubuntu/ jammy universe

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal universe

deb http://nl.archive.ubuntu.com/ubuntu/ jammy-updates universe

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal-updates universe



## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 

## team, and may not be under a free licence. Please satisfy yourself as to 

## your rights to use the software. Also, please note that software in 

## multiverse WILL NOT receive any review or updates from the Ubuntu

## security team.

deb http://nl.archive.ubuntu.com/ubuntu/ jammy multiverse

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal multiverse

deb http://nl.archive.ubuntu.com/ubuntu/ jammy-updates multiverse

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal-updates multiverse



## N.B. software from this repository may not have been tested as

## extensively as that contained in the main release, although it includes

## newer versions of some applications which may provide useful features.

## Also, please note that software in backports WILL NOT receive any review

## or updates from the Ubuntu security team.

deb http://nl.archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse

# deb-src http://nl.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse





deb http://security.ubuntu.com/ubuntu jammy-security main restricted

# deb-src http://security.ubuntu.com/ubuntu focal-security main restricted

deb http://security.ubuntu.com/ubuntu jammy-security universe

# deb-src http://security.ubuntu.com/ubuntu focal-security universe

deb http://security.ubuntu.com/ubuntu jammy-security multiverse

# deb-src http://security.ubuntu.com/ubuntu focal-security multiverse



# This system was installed using small removable media

# (e.g. netinst, live or single CD). The matching "deb cdrom"

# entries were disabled at the end of the installation process.

# For information about how to configure apt package sources,

# see the sources.list(5) manual.

# deb [arch=amd64] https://download.docker.com/linux/ubuntu jammy stable # uitgeschakeld bij opwaardering naar jammy

# deb-src [arch=amd64] https://download.docker.com/linux/ubuntu focal stable

SECOND EDIT:

jan@Ubuntu-20-04:~$ sudo apt update

[sudo] wachtwoord voor jan: 

Geraakt:1 http://nl.archive.ubuntu.com/ubuntu jammy InRelease                                                                                                              

Ophalen:2 http://security.ubuntu.com/ubuntu jammy-security InRelease [110 kB]                                                                                              

Geraakt:3 http://nl.archive.ubuntu.com/ubuntu jammy-updates InRelease                                                                                                 

Geraakt:4 http://nl.archive.ubuntu.com/ubuntu jammy-backports InRelease                                                                                               

Geraakt:5 https://ppa.launchpadcontent.net/deadsnakes/ppa/ubuntu jammy InRelease   

110 kB opgehaald in 2s (54,3 kB/s)                        

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